Liquid crystal display devices have a significantly reduced depth and will dissipate much less power than other kinds of display devices. By taking advantage of these features, liquid crystal display devices have recently been used extensively in various kinds of information devices including laptop personal computers, cellphones, and electronic organizers and videotape recorders with a built camera and an LCD monitor.
Each of those various kinds of display devices represents colors by adding together the colors red, green and blue that are the three primary colors of light. A liquid crystal display device generally includes an illumination unit which emits white light (i.e., a backlight), and color filters which selectively transmit red, green and blue light rays (i.e., red, green and blue color filters) are respectively arranged to face red, green and blue pixels of a liquid crystal display panel.
A “striped arrangement” is currently adopted most extensively as the arrangement of those color filters. According to the striped arrangement, red, green and blue color filters are arranged in stripes so as to run vertically (i.e., longitudinally) on the display screen. When the striped arrangement is adopted, each pixel usually has a rectangular shape with an aspect ratio of three to one so that a single color display pixel has a square shape.
Meanwhile, a so-called “delta arrangement” is also known. According to the delta arrangement, red, green and blue color filters are arranged so that a triangle is formed if their centers are connected together with a line. The delta arrangement can be used effectively to display a natural image, and therefore, is mainly adopted in the viewfinders of camcorders and digital cameras. When the delta arrangement is adopted, each pixel normally has a square shape.
Furthermore, to improve the viewing angle characteristic of liquid crystal display devices, an alignment division type vertical alignment (VA) mode has also been proposed recently. The VA mode is a display mode in which liquid crystal molecules are aligned substantially perpendicularly to the surface of the substrate when no voltage is applied thereto. In this description, the “alignment division” means dividing a single pixel into multiple regions in which liquid crystal molecules get aligned in mutually different orientations upon the application of a voltage.
Examples of the alignment division type vertical alignment modes include the MVA (Multi-domain Vertical Alignment) mode disclosed in Patent Document No. 1 and the CPA (Continuous Pinwheel Alignment) mode disclosed in Patent Document No. 2.
According to the MVA mode, the alignment division is done by alignment control structures which are provided for both of two substrates that face each other with a liquid crystal layer interposed between them. As the alignment control structures, slits cut through electrodes and/or ribs provided on electrodes may be used. Under the alignment controlling force exerted by these alignment control structures, typically four liquid crystal domains are formed within a single pixel upon the application of a voltage.
According to the CPA mode, the alignment division is done by an oblique electric field generated at an edge portion of a pixel electrode and an oblique electric field generated at a notch and/or hole which has been cut through the pixel electrode. Upon the application of a voltage, liquid crystal molecules are aligned radially (i.e., axisymmetrically). That is to say, a single pixel is divided into multiple regions in which liquid crystal molecules are aligned in mutually different orientations.